The present invention relates, in general, to a plastics processing machine, and more particularly to a drive apparatus for a plastics processing machine.
Nothing in the following discussion of the state of the art is to be construed as an admission of prior art.
German Pat. No. DE 100 28 066 C1 discloses an injection unit which is driven by two electric motors disposed in alignment to one another. One electric motor acts via a threaded nut upon the driveshaft of a screw to cause a translational movement, whereas the other electric motor acts upon a driving pin to cause a rotational movement of the driveshaft. A coupling is disposed between the motor shafts of both motors, with both motor shafts constructed as hollow shafts which are rotatably mounted on the housing of the injection unit. Respective bearings are provided on the respective hollow shafts.
German patent publication no. DE 199 09 307 A1 discloses a production machine with electric drives for use in the plastics industry. The production machine, e.g. an injection molding machine, extruder, or blow molding machine, includes an electric drive for moving a material feed element, with at least one of the electric drives being constructed as direct electric drive. The electric motor may be implemented as synchronous motor or asynchronous motor. A hollow shaft for receiving the driveshaft of an extruder screw for example projects through the rotor of the electric motor.
It would be desirable and advantageous to provide an improved drive apparatus which is compact and is constructed for easy disassembly, if need be, and yet is reliable in operation.